Portable medical imaging system

ABSTRACT

A medical imaging system includes a movable station and a gantry. The movable station includes a gantry mount rotatably attached to the gantry. The gantry includes an outer C-arm slidably mounted to and operable to slide relative to the gantry mount, an inner C-arm slidably coupled to the outer C-arm and, an imaging signal transmitter and sensor attached to the C-arms. The two C-arms work together to provide a full 360 degree rotation of the imaging signal transmitter.

TECHNICAL FIELD

The present invention relates to medical imaging systems.

BACKGROUND OF THE INVENTION

Healthcare practices have shown the tremendous value ofthree-dimensional imaging such as computed tomography (CT) imaging, as adiagnostic tool in the Radiology Department. These imaging systemsgenerally contain a fixed bore into which the patient enters from thehead or foot. Other areas of care, including the operating room,intensive care departments and emergency departments, rely ontwo-dimensional imaging (fluoroscopy, ultrasound, 2-D mobile X-ray) asthe primary means of diagnosis and therapeutic guidance.

While mobile solutions for ‘non-radiology department’ andpatient-centric 3-D imaging do exist, they are often limited by theirfreedom of movement to effectively position the system without movingthe patient. Their limited freedom of movement has hindered theacceptance and use of mobile three-dimensional imaging systems.

Therefore, there is a need for a small scale and/or mobilethree-dimensional imaging systems for use in the operating room,procedure rooms, intensive care units, emergency departments and otherparts of the hospital, in ambulatory surgery centers, physician offices,and the military battlefield, which can access the patients in anydirection or height and produce high-quality three-dimensional images.

SUMMARY OF THE DISCLOSURE

According to one aspect of the present invention, a novel medicalimaging system is provided. The system includes a movable station and agantry. The movable station includes a gantry mount rotatably attachedto the gantry. The gantry includes a first C-arm slidably mounted to andoperable to slide relative to the gantry mount, a second C-arm slidablycoupled to the first C-arm and, an imaging signal transmitter attachedto one of the C-arms and an imaging sensor mounted to one of the C-arms.The two C-arms work together to provide a full 360 degree rotation ofthe imaging signal transmitter.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective rear view of an imaging system according to oneembodiment of the present invention.

FIG. 2 is a schematic diagram of an imaging controller system 40according to one embodiment of the present invention.

FIG. 3 is a perspective front view of the imaging system of FIG. 1.

FIG. 4 is a perspective view of the imaging system of FIG. 1 in whichthe gantry has been rotated about the X-axis by 90 degrees.

FIG. 5 is a perspective view of the gantry partially showing a cablingarrangement.

FIG. 6 is a perspective view of the gantry showing the cablingarrangement.

FIG. 7 is a side view of the gantry showing the cabling arrangement.

FIG. 8 illustrates a motor assembly for telescopically controlling theC-arms of the gantry.

FIGS. 9A-G illustrate the 360 degree rotation of the gantry in 60 degreeincrements.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of this application, the terms “code”, “software”,“program”, “application”, “software code”, “software module”, “module”and “software program” are used interchangeably to mean softwareinstructions that are executable by a processor. A “user” can be aphysician or other medical professional.

FIG. 1 is a schematic diagram showing an imaging system 10, such as acomputerized tomographic (CT) x-ray scanner, in accordance with oneembodiment of the invention. The imaging system 10 includes a movablestation 60 and a gantry 56. The movable station includes a verticalshaft 59 and a gantry mount 58 which is rotatably attached to thevertical shaft. The movable station 60 includes two frontomni-directional wheels 62 and two rear omni-directional wheels 64,which together provide movement of the movable station 60 in anydirection in an X-Y plane. The omni-directional wheels 62,64 can beobtained, for example, from Active Robots Limited of Somerset, U.K. Apair of handles 13 mounted to the housing of the movable station 60allow a user to manually maneuver the station.

A motor 66 attached to the vertical shaft 59 is designed to rotate thegantry mount 58 full 360 degrees about the X-axis and a motor 67 movesthe gantry mount 58 vertically along the z-axis under the control of thecontrol module 51.

The gantry 56 includes a first C-arm 70 slidably coupled to the gantrymount 58 and a second C-arm 72 which is slidably coupled to the firstC-arm. In the embodiment shown, the first and second C-arms 70,72 areouter and inner C-arms, respectively. In the embodiment shown, the outerand inner C-arms 70,72 are circular in shape and rotatecircumferentially about a central axis so as to allow imaging of apatient who is lying in bed 16 without the need to transfer the patient.

An imaging signal transmitter 74 such as an X-ray beam transmitter ismounted to one side of the second C-arm 72 while an imaging sensor 74such as an X-ray detector array is mounted to the other side of thesecond C-arm and faces the transmitter. In operation, the X-raytransmitter 74 transmits an X-ray beam which is received by the X-raydetector 76 after passing through a relevant portion of a patient (notshown).

In one embodiment, the system 10 is a multi-modality x-ray imagingsystem designed with surgery in mind. The three imaging modalitiesinclude fluoroscopy, 2D Radiography, and Cone-beam CT. Fluoroscopy is amedical imaging technique that shows a continuous X-ray image on amonitor, much like an X-ray movie. 2D Radiography is an imagingtechnique that uses X-rays to view the internal structure of anon-uniformly composed and opaque object such as the human body. CBCT(cone beam 3D imaging or cone beam computer tomography) also referred toas C-arm CT, is a medical imaging technique consisting of X-ray computedtomography where the X-rays are divergent, forming a cone.

The movable station 60 includes an imaging controller system 40 whichserves a dual function of (1) controlling the movement of theomni-directional wheels 62,64, gantry mount 58 and the gantry 56 toposition the imaging signal transmitter 74 in relation to the patient,and (2) controlling imaging functions for imaging the patient once thegantry 56 has been properly positioned.

Referring now to FIG. 2, the imaging controller system 40 of the presentinvention is connected to a communication link 52 through an I/Ointerface 42 such as a USB (universal serial bus) interface, whichreceives information from and sends information over the communicationlink 52. The imaging controller system 40 includes memory storage 44such as RAM (random access memory), processor (CPU) 46, program storage48 such as ROM or EEPROM, and data storage 50 such as a hard disk, allcommonly connected to each other through a bus 53. The program storage48 stores, among others, imaging control module 54 and motion controlmodule 51, each containing software to be executed by the processor 46.The motion control module 51 executed by the processor 46 controls thewheels 62,64 of the movable station 60 and various motors in the gantrymount 58 and gantry 56 to position the station 60 near the patient andposition the gantry in an appropriate position for imaging a relevantpart of the patient.

The imaging control module 54 executed by the processor 46 controls theimaging signal transmitter 74 and detector array 76 to image the patientbody. In one embodiment, the imaging control module images differentplanar layers of the body and stores them in the memory 44. In addition,the imaging control module 54 can process the stack of images stored inthe memory 44 and generate a three dimensional image. Alternatively, thestored images can be transmitted to a host system (not shown) for imageprocessing.

The motion control module 51 and imaging control module 54 include auser interface module that interacts with the user through the displaydevices 11 a and 11 b and input devices such as keyboard and buttons 12and joy stick 14. Strain gauges 13 mounted to the handles 15 are coupledto the I/O device 42 and conveniently provide movement of the movablestation 12 in any direction (X, Y, Wag) while the user is holding thehandles 15 by hand as will be discussed in more detail below. The userinterface module assists the user in positioning the gantry 56. Any ofthe software program modules in the program storage 48 and data from thedata storage 50 can be transferred to the memory 44 as needed and isexecuted by the CPU 46. The display device 11 a is attached to thehousing of the movable station 60 near the gantry mount 58 and displaydevice 11 b is coupled to the movable station through three rotatabledisplay arms 16, 18 and 20. First display arm 16 is rotatably attachedto the movable station 60, second display arm 18 is rotatably attachedto the first arm 16 and third display arm 20 is rotatably attached tothe second display arm. The display devices 11 a,11 b can have touchscreens to also serve as input devices through the use of user interfacemodules in the modules 51 and 54 to provide maximum flexibility for theuser.

Navigation markers 68 placed on the gantry mount 58 are connected to theimaging controller system 40 through the link 52. Under the control ofthe motion control module 51, the markers 68 allow automatic orsemi-automatic positioning of the gantry 56 in relation to the patientbed or OR (operating room) table via a navigation system (not shown).The markers 68 can be optical, electromagnetic or the like.

Information can be provided by the navigation system to command thegantry 56 or system 10 to precise locations. One example would be asurgeon holding a navigated probe at a desired orientation that tellsthe imaging system 10 to acquire a Fluoro or Radiographic image alongthat specified trajectory. Advantageously, this will remove the need forscout shots thus reducing x-ray exposure to the patient and OR staff.The navigation markers 68 on the gantry 56 will also allow for automaticregistration of 2D or 3D images acquired by the system 10. The markers68 will also allow for precise repositioning of the system 10 in theevent the patient has moved.

In the embodiment shown, the system 10 provides a large range of motionin all 6-degrees of freedom (“DOF”). Under the control of the motioncontrol module 51, there are two main modes of motion: positioning ofthe movable station 60 and positioning of the gantry 56.

The movable station 60 positioning is accomplished via the fouromni-directional wheels 62,64. These wheels 62,64 allow the movablestation 60 to be positioned in all three DOF about the horizontal plane(X,Y,Wag). “Wag” is a system 10 rotation about the vertical axis(Z-axis), “X” is a system forward and backward positioning along theX-axis, and “Y” is system 10 lateral motion along the Y-axis. Under thecontrol of the control module 51, the system 10 can be positioned in anycombination of X, Y, and Wag (Wag about any arbitrary Z-axis due to useof omnidirectional wheels 62,64) with unlimited range of motion. Inparticular, the omni-directional wheels 62,64 allow for positioning intight spaces, narrow corridors, or for precisely traversing up and downthe length of an OR table or patient bed.

The gantry 56 positioning is accomplished about (Z, Tilt, Rotor). “Z” isgantry 56 vertical positioning, “Tilt” is rotation about the horizontalaxis parallel to the X-axis as described above, and “Rotor” is rotationabout the horizontal axis parallel to the Y-axis as described above.

Together with the movable station 60 positioning and gantry 56positioning, the system 10 provides a range of motion in all 6 DOF (X,Y, Wag, Z, Tilt and Rotor) to place the movable station 60 and theimaging transmitter 74 and sensor 76 precisely where they are needed.Advantageously, 3-D imaging can be performed regardless of whether thepatient is standing up, sitting up or lying in bed and without having tomove the patient.

Precise positions of the system 10 can be stored in the storage memory50 and recalled at any time by the motion control module 51. This is notlimited to gantry 56 positioning but also includes system 10 positioningdue to the omni-directional wheels 62,64.

As shown in FIG. 3, each of the gantry mount 58, outer C-arm 70 andinner C-arm 72 respectively has a pair of side frames 86, 88,90 thatface each other. A plurality of uniformly spaced rollers 84 are mountedon the inner sides of the side frames 86 of the gantry mount 58. Theouter C-arm 70 has a pair of guide rails 78 on the outer sides of theside frames 88. The rollers 84 are coupled to the guide rails 78. Asshown, the rollers 84 and the guide rails 78 are designed to allow theouter C-arm 78 to telescopically slide along the gantry mount 58 so asto allow at least 180 degree rotation of the C-arm about its centralaxis relative to the gantry mount.

A plurality of uniformly spaced rollers 80 are mounted on the innersides of the side frames 88 of the outer C-arm 70. The inner C-arm 72has a pair of guide rails 82 on the outer sides of the side frames 90.The rollers 80 are coupled to the guide rails 82. As shown, the rollers80 and the guide rails 82 are designed to allow the inner C-arm 72 totelescopically slide along the outer C-arm 70 so as to allow at least180 degree rotation of the C-arm about its central axis relative to theouter C-arm.

Thus, the present invention as disclosed herein advantageously allowsthe gantry 56 to rotate about its central axis a full 360 degrees toprovide the maximum flexibility in positioning the imaging system 10with minimum disturbance of the patient.

In another aspect of the present invention, a unique cabling arrangementis provided to make the imaging system 10 more compact and visually moreappealing. As shown in FIGS. 5 and 6, a cable carrier/harness 92contains electrical cables to carry signals between the imagingcontroller system 40 and various motors, X-ray transmitter 74, imagingsensor 76 and various electronic circuits in the gantry 56. A firstcable router 94 is mounted to the outer surface of the outer C-arm 70and a second cable router 96 is mounted to the outer surface of theinner C-arm 72. Each cable router 94,96 has a through-hole 95,97 throughwhich the cable carrier 92 passes.

The cable carrier 92 extends from the gantry mount 56 over the outersurface of the first C-arm 70, through the through-hole 95 of the firstcable router 94 and over an outer surface of the second C-arm 72. Thecable carrier 92 overlying the first C-arm 70 extends in a firstcircumferential direction (clock-wise as shown) 98 and enters the firstcable router 94 in a second circumferential direction (counterclock-wise as shown) 99 opposite to the first circumferential directionto create a 180 degree service loop over the outer surface of the firstC-arm.

From there, the cable carrier 92 extends in the first circumferentialdirection 98 and enters the second cable router in the secondcircumferential direction 99 to create another service loop over theouter surface of the second C-arm 72.

The particular locations of the first and second cable routers 94,96combined with the service loops allow slack in the cable carrier 92 toprovide the gantry 56 with full 360 degrees rotation without tangling orcausing stress in the cable carrier. In the embodiment shown, therouters are mounted near the midpoint of the C-arms.

FIG. 8 illustrates one embodiment of a motor assembly 100 that could beused to telescopically rotate the outer C-arm 70 relative to the gantrymount 58 and inner C-arm 72 relative to the outer C-arm. Each motorassembly 100 includes a servo motor 102 with encoder feedback, gear box104 to change the turning ratio, drive pulley 106, idler pulleys 108 andbelt 110 threaded between the drive pulley and the idler pulleys. Onemotor assembly 100 is mounted to the gantry mount to move the outerC-arm 70 relative to the gantry mount and another motor assembly ismounted to the outer C-arm 70 near the center of the arm to move theinner C-arm 70 relative to the outer C-arm.

FIGS. 9A-9G illustrate the 360 degree rotation of the gantry 56 in thecounter-clockwise direction in 60 degree increments with FIG. 9Arepresenting a zero degree position of the imaging sensor 76 andtransmitter 74. FIG. 9B represents a 60 degree turn/position of thegantry 56. For each 60 degree turn of the gantry 56, the motorassemblies 100, under the control of the motion control module 51, turnthe inner C-arm 72 by 30 degrees counter-clock wise and also turn theouter C-arm 70 by 30 degrees counter-clock wise for a combined 60 degreeturn. FIG. 9G represents a full 360 degree turn of the gantry 56. As canbe seen, the outer C-arm 70 and inner C-arm 72 have each moved 180degrees from the original zero degree position of FIG. 9A.

As described above in detail, the present invention in variousembodiments provide the following benefits: (1) movement of the systemin any X-Y direction with Wag about any Z-axis from the use ofomni-directional wheels 62,64; (2) double telescoping C-gantry for full360-degree imaging beam rotation; (3) imaging while lying in bed,sitting or standing such as standing CBCT; (4) storage and recall ofsystem 10 and gantry 56 positions; (5) quasi-simultaneous multi-planarx-ray imaging; (6) recall of positions via robotics or navigationcoordinates.

The foregoing specific embodiments represent just some of the ways ofpracticing the present invention. Many other embodiments are possiblewithin the spirit of the invention. Accordingly, the scope of theinvention is not limited to the foregoing specification, but instead isgiven by the appended claims along with their full range of equivalents.

What is claimed is:
 1. A medical imaging system comprising: a movablestation; a gantry mount attached to the movable station; a gantryrotatably attached to the gantry mount and including: a first C-armslidably mounted to and operable to slide relative to the gantry mount;a second C-arm slidably coupled to the first C-arm; and an imagingsignal transmitter attached to one of the first and second C-arms, thefirst and second C-arms together providing a 360 degree rotation of theimaging signal transmitter; an imaging sensor mounted to one of thefirst and second C-arms.
 2. The medical imaging system of claim 1,further comprising: a controller; at least three omni-directional wheelsattached to the movable station and adapted to be controlled by thecontroller, the omni-directional wheels providing the movable stationwith three degrees of freedom (X,Y,Wag) about a horizontal plane.
 3. Themedical imaging system of claim 2, further comprising strain gaugesmounted to the movable station to allow a user to control movement ofthe omni-directional wheels under the control of the controller.
 4. Themedical imaging system of claim 2, further comprising: a first motorthat provides a sliding movement of the first C-arm relative to thegantry mount; and a second motor that provides a sliding movement of thefirst C-arm relative to the second C-arm.
 5. The medical imaging systemof claim 1, further comprising: a cable carrier containing a pluralityof electrical cables; a first cable router having a through-hole andmounted to an outer surface of the first C-arm, the cable carrierextending from the gantry mount over the outer surface of the firstC-arm, through the through-hole of the first cable router and over anouter surface of the second C-arm.
 6. The medical imaging system ofclaim 5, wherein the cable carrier extends in a first circumferentialdirection and enters the first cable router in a second circumferentialdirection opposite to the first circumferential direction to create a180 degree service loop over the outer surface of the first C-arm. 7.The medical imaging system of claim 5, further comprising a second cablerouter having a through-hole and mounted to an outer surface of thesecond C-arm, the cable carrier extending through the through-hole ofthe second cable router.
 8. The medical imaging system of claim 7,wherein the cable carrier extends in a first circumferential directionand enters the second cable router in a second circumferential directionopposite to the first circumferential direction to create a service loopover the outer surface of the second C-arm.
 9. The medical imagingsystem of claim 5, further comprising: a cable carrier containing aplurality of electrical cables; a first cable router having athrough-hole and mounted to an outer surface of the first C-arm, thecable carrier extending from the gantry mount over the outer surface ofthe first C-arm, through the through-hole of the first cable router andover an outer surface of the second C-arm; a second cable router havinga through-hole and mounted to an outer surface of the second C-arm, thecable carrier extending through the through-hole of the second cablerouter;. wherein the cable carrier extends in a first circumferentialdirection and enters the first cable router in a second circumferentialdirection opposite to the first circumferential direction to create a180 degree service loop over the outer surface of the first C-arm; andwherein the cable carrier extends in the first circumferential directionand enters the second cable router in the second circumferentialdirection to create a second 180 degree service loop over the outersurface of the second C-arm.
 10. A medical imaging system that providesa 6-degree of freedom movement comprising: a movable station includingat least four omni-directional wheels attached to and adapted toposition the movable station in all three degrees of freedom (X, Y andWag) about an x-y horizontal plane; a gantry mount rotatably attached tothe movable station; a gantry rotatably attached to the gantry mount andincluding: a first C-arm slidably mounted to and adapted to sliderelative to the gantry mount in a circumferential direction; a secondC-arm slidably coupled to and adapted to slide relative to the firstC-arm in a circumferential direction; and an imaging signal transmitterattached to one of the first and second C-arms, the first and secondC-arms together providing a 360 degree rotation of the imaging signaltransmitter; an imaging sensor mounted to one of the first and secondC-arms.
 11. The medical imaging system of claim 10, further comprising:a controller coupled to the omni-directional wheels; and a joystickmounted to the movable station to allow a user to control movement ofthe omni-directional wheels under the control of the controller.
 12. Themedical imaging system of claim 10, further comprising: a first motorthat provides a sliding movement of the first C-arm relative to thegantry mount; and a second motor that provides a sliding movement of thefirst C-arm relative to the second C-arm.
 13. The medical imaging systemof claim 10, further comprising: a cable carrier containing a pluralityof electrical cables; a first cable router having a through-hole andmounted to an outer surface of the first C-arm, the cable carrierextending from the gantry mount over the outer surface of the firstC-arm, through the through-hole of the first cable router and over anouter surface of the second C-arm.
 14. The medical imaging system ofclaim 13, wherein the cable carrier extends in a first circumferentialdirection and enters the first cable router in a second circumferentialdirection opposite to the first circumferential direction to create a180 degree service loop over the outer surface of the first C-arm. 15.The medical imaging system of claim 13, further comprising a secondcable router having a through-hole and mounted to an outer surface ofthe second C-arm, the cable carrier extending through the through-holeof the second cable router.
 16. The medical imaging system of claim 15,wherein the cable carrier extends in a first circumferential directionand enters the second cable router in a second circumferential directionopposite to the first circumferential direction to create a service loopover the outer surface of the second C-arm.
 17. The medical imagingsystem of claim 10, further comprising: a cable carrier containing aplurality of electrical cables; a first cable router having athrough-hole and mounted to an outer surface of the first C-arm, thecable carrier extending from the gantry mount over the outer surface ofthe first C-arm, through the through-hole of the first cable router andover an outer surface of the second C-arm; a second cable router havinga through-hole and mounted to an outer surface of the second C-arm, thecable carrier extending through the through-hole of the second cablerouter; wherein the cable carrier extends in a first circumferentialdirection and enters the first cable router in a second circumferentialdirection opposite to the first circumferential direction to create a180 degree service loop over the outer surface of the first C-arm; andwherein the cable carrier extends in the first circumferential directionand enters the second cable router in the second circumferentialdirection to create a second 180 degree service loop over the outersurface of the second C-arm.